Laminated glass



April 1958 R. A. GAISER 2,831,792

LAMINATED cuss Filed D60. 21, 1954 zoef vope A TTORNE Y5 nited StatesPatent LAMINATED GLASS Romey A. Gaiser, Toledo, Ohio, assignor toLibbey- Owens-Ford Glass Company, Toledo, Ohio, at corporation of OhioApplication December 21, 1954, Serial No. 476,663

10 Claims. (Cl. 1542.73)

The present invention relates to special laminated glass structures, andmore particularly to an improved process and apparatus for forminglaminated glass.

The type of laminated glass structure with which this invention isparticularly concerned comprises two sheets of glass and an interposedlayer of non-brittle plastic adherent thereto to provide a compositestructure and in which a surface of at least one of the glass sheets isprovided with a transparent electrically conductive film. Suchlaminated, electrically conducting structures have come to be widelyused in preventing fogging and icing conditions on aircraft windows andother vehicles and heretofore have been formed by conventionallaminating apparatus and techniques involving the application ofexternal heat and pressure which of course require the use of large andexpensive equipment.

Broadly stated, the present invention proposes to apply heat internallyto heat the plastic to a laminating temperature preferably by means ofan electrically conductive film which may be adhered to at least one ofthe glass sheets.

It is a primary object of this invention to provide a process oflaminating glass which is relatively simple and inexpensive requiring arelatively small expenditure in laminating equipment.

Another object of the invention is to provide a process for laminatingglass without the use of an external heat source.

A still further object of the invention is to provide a process oflaminating glass which is neat and clean.

Other objects and advantages of the invention will be- :ome moreapparent during the course of the following description when taken inconnection with the accom- Janying drawings.

In the drawings wherein like numerals are employed to iesignate likeparts throughout the same:

Fig. 1 is a perspective view of a laminated glass struczure madeaccording to the invention;

Fig. 2 is a fragmentary perspective view showing the felationship of theseparated components of the laminated iandwich structure shown in Fig.1;

Fig. 3 is a perspective view showing the laminating aparatus of theinvention;

Fig. 4 is a fragmentary sectional view taken substan- :ially along lines44 of Fig. 3; and

Fig. 5 is a partial sectional view taken along lines 5-5 )f Fig. 1.

Referring now more particularly to the drawings, there s shown in Fig. 1an electrically conducting laminated glass structure of the general typequite commonly used n aircraft glazing. More particularly, as may bebest seen n Fig. 2, the laminated sandwich structure comprises two:heets of glass 11 and 12, an interposed layer of non Jrittle plastic13, and an electrically conducting film 14 m the glass sheet 12 providedwith suitable electrodes or :us bars 15. The plastic interlayer 13 ispreferably formed formed of synthetic resinous material such as, for

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example, polyvinyl butyral. However, different plastics varying inthickness and physical characteristics may be employed and the inventionis not limited to the use of any particular resin.

The transparent electrically conducting film 14 may be formed of tinoxide which may be applied in a number of different ways, as by themethod described in Patent No. E,-'-l29,-'.2 granted October 21, 1947,to H. A. McMaster. Or, the film may be formed of a metal selected fromthe group consisting of gold, silver, copper, iron, and nickel asdescribed in Patent No. 2,628,927, issued February 17, 1953, to WilliamH. Colbert, Willard L. Morgan, and Arthur R. Weinrich. As noted above,and as may be seen in Figs. 1 and 2, the electrodes 15 extend along apair of marginal edges of the sheet 12 in contact with the electricallyconducting film 14. The electrodes may be of any one of a number ofdifferent materials which can be applied in any convenient manner. Forexample, electrodes of sprayed copper, sprayed copper alloy baked ongold, silver, and platinum fluxes and combinations of these metals haveall been used satisfactorily.

In fabricating the laminated glass structure it), the laminations mayfirst be cut to the desired size and then assembled in sandwich form.Any suitable jig means or the like can be employed to position theplastic layer 13 between the glass sheets 11 and 12 with the filmed orcoated surface 14 of the glass sheet 12 preferably facing inwardly andlying adjacent the interlayer 13. As thus assembled, there is presentbetween the laminations undesirable air, moisture, and/or gas which mustbe removed in order that an efiicient bond be obtained between therespective laminae. It is therefore desirable, although not necessary inall cases, to dry out the excess air and moisture by passing theassembly between one or more curved or semi-resilient pressing rollersbefore the sandwich is ready to be subjected to the heat and pressurerequired to bond the laminae together.

To accomplish this bonding effect, according to the present invention,the superimposed sheets 10 and 11 and plastic interlayer 13 are piacedin a suitable plastic bag 16 such as shown in Fig. 3. The plastic bag 16is formed of two sheets or layers of an air impervious plastic material17 and 18 which are sealed together around their marginal edge portionsas at 39. if desired, three sides of the sheets 17 and 18 may be sealedbefore the components of the laminated structure 10 are insertedtherein, and after the glass has been placed in the bag thus formed, thelourth side may be sealed by a heating element or other suitable sealingmeans to complete the air tight sealing v; t e bag. As may be seen. inFigs. 3 and 4, the seal is fer-cell around the leads or extensions 20which are suitably connected to the electrodes or bus bars 15 thusallowing them to extend outwardly of the bag for a purpose to bedescribed hereinbelow.

After the plastic bag 16 has lnecn sealed around its entire marginalperiphery, the air remaining in the bag may be extracted by means of asuitable conduit or tube 21 connected to a vacuum source not shown. Thevacuum tube is sealed between the marginal edges of the sheets 17 and 18and extends into the interior of the bag adjacent the sealed marginaledge 19. By extracting the air within the bag, the laminae are subjectedto a pressure by the atmosphere on the outside of the bag which fur therforces the air from between the laminate and also assures uniformcontact between the plastic intcr layer 13 and the sheets i1 and 12.

in order to supply heat to the plastic intcrlayer 13, so as to allow itto form the bond between the respective sheets, power is supplied to thelectrodes 15 from an external source, not shown, through the leads 20 toheat the electrically conducting coating 14 to a temperature suflicientto raise the temperature of the interlayer 13 to a laminatingtemperature. This temperature is generally between 180 and 220 F.,depending of course on the characteristics of the plastic used,although, it may in some instances be higher or lower. Of course, thelength of time required to laminate the structure will depend on thelamination temperature of the plastic, the resistance and heatingcharacteristics of the electrically conductive coating, and the powersupplied to the coating.

Upon completing the laminating process, the power is turned off and thebag 16 may be removed from the laminated structure and disposed of. Or,the bag may be cut along one edge and used for a subsequent operationwhere smaller sheets are to be laminated.

It will thus be evident that all of the head necessary to laminate thesheets together is supplied through the electrically conducting film 14which eliminates the necessity for large external heating units.Furthermore. because of the very simple plastic bag that is used, largepressure units are not required and thus the laminated structure may beproduced relatively inexpensively. While only two sheets of glass havebeen shown to be laminated, it of course is within the realm of theinvention to produce laminated articles which are made up of three ormore sheets.

It is also to be understood that the form of this invention disclosedherein is to be taken as the preferred embodiment thereof, and thatvarious changes in the shape, size and arrangement of parts may beresorted to without departing from the spirit of the invention or thescope of the following claims.

I claim:

1. In a method of laminating glass sheets, the steps of arranging glasssheets and an interposed plastic layer in superimposed relation withrespect to one another to produce a sandwich, and heating the contactingfaces of the laminations to a greater temperature than the outside facesof the lamination by heat applied between at least one of said glasssheets and said plastic layer to heat the plastic layer to laminatingtemperature and thereby ellect a bond between said glass sheets and saidplastic layer.

2. In a method of laminating glass sheets, the steps of arranging atleast one glass sheet and a plastic layer in superimposed relation withrespect to one another to prcduce a sandwich, and heating the contactingfaces of the lamination from a source of heat located inside thestructure and between a glass sheet and said plastic layer to heat theplastic layer to laminating temperature to thereby effect a bond betweensaid glass she ts and said plastic layer.

3. In a method of laminating glass sheets, the steps of arranging atleast one glass sheet and a plastic layer in superimposed relation withrespect to one another to pro duce a sandwich, and heating said plasticlayer to laminating temperature by a heating element in direct contactwith both a glass sheet and said plastic layer to effect Zl bond betweensaid glass sheets and said plastic layer.

4. A method of forming a laminated structure of a plurality of laminaeof sheet material with at least one of said sheets being of a plasticmaterial, including the steps of arranging a plurality of said laminaein superimposed relation with respect to one another to form a sandwich,and heating said plastic material to a higher temperature than theoutside faces of the lamination by heat applied to the inside andbetween one of said glass sheets and said plastic layer of said sandwichto laminate said sheets together.

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5. In a method of forming a laminating structure of a plurality oflaminae of sheet material with at least one of said sheets being of aplastic material, the steps of arranging the plurality of laminae insuperimposed relation with respect to one another to form a sandwich,applying outside pressure to said sandwich to force air from betweensaid laminae, and applying heat to said sandwich internally from asource of heat located between one of said glass sheets and said plasticlayer to fur-L; sui l g' astic layer to laminating temperature tolumil'ia ic said sheets together.

6. in a method of laminating sheet material with at least one of saidsheets having an electrically conducting film thereon by an interposedlayer of plastic maic izil. the steps of arranging a plurality of saidsheets uni said plastic material in superimposed relation with respectto one another to form a sandwich with said electrically conductingcoating on one of said sheets in rcntact with said plastic, andsupplying power to said electrically conducting film to heat saidplastic material to at least the laminating temperature thereof to causesaid plastic layer to bond to said sheets.

7. in the method of laminating sheet material together by a layer ofplastic material with at least one of said sheets having an electricallyconducting film thereon, the steps of arranging said sheets and saidplastic layer in superimposed relation with one another to form asandwich, placing said sandwich in a plastic bag and sealing saidsandwich in said bag, removing air from said bag, and heating saidplastic layer by applying power to said electrically conducting film.

8. In the method of laminating sheet material together by a layer ofplastic material with at least one of said sheets having an electricallyconducting film thereon, the steps of arranging a plurality of saidsheets in superimposed relation with respect to one another and withrespect to a layer of said plastic material with said electricallyconducting film on one of said sheets in contact with said plasticlayer, removing the air from between said sheets and layers while saidsandwich is in air tight container, and applying power to saidelectrically conducting film to heat said plastic layer to thelaminating temperature thereof to cause said plastic layer to bond saidsheets together.

9. A method of producing an electrically conducting laminated articlewhich comprises applying an electrically conducting film to a surface ofa sheet, assembling said sheet with a layer of plastic material incontact with said electrically conducting film, and supplying power tosaid electrically conducting film to heat said plastic material to atleast the laminating temperature thereof to cause said plastic layer tobond to said sheet.

10. A method of producing electrically conducting laminated safetyglass, the steps of applying a transparent electrically conducting filmcomprising essentially tin oxide to the surface of one of the glasssheets to be laminated, assembling said filmed sheet together withanother glass sheet and an interposed layer of plastic, supplying powerto said electrically conducting film while in said assembly to heat saidplastic material and cause it to bond to said glass sheets.

References Cited in the file of this patent UNITED STATES PATENTS

1. IN A METHOD OF LAMINATING GLASS SHEETS, THE STEPS OF ARRANGING GLASSSHEETS AND AN INTERPOSED PLASTIC LAYER IN SUPERIMPOSED RELATION WITHRESPECT TO ONE ANOTHER TO PRODUCE A SANDWICH, AND HEATING THE CONTACTINGFACES OF THE LAMINATIONS TO A GREATER TEMPERATURE THAN THE OUTSIDE FACESOF THE LAMINATION BY HEAT APPLIED BETWEEN AT LEAST ONE OF SAID GLASSSHEETS AND SAID PLASTIC LAYER TO HEAT THE PLASTIC LAYER TO LAMINATINGTEMPERATURE AND THEREBY EFFECT A BOND BETWEEN SAID GLASS SHEETS AND SAIDPLASTIC LAYER.